A common problem associated with the use of electronic devices and tools is the necessity of powering such electronic devices. Power cords connected to an external power source provide sufficient power, but are an obtrusive and problematic interference, especially with regard to power tools which are desirably easily manipulated in and around workspaces that are often crowded and obstructed.
Further, power cords and external power sources adapted for use with power tools are typically unavailable for power tools in mobile applications. For example a user may need a power tool in a variety of locations, and it may be unfeasible to feed a power connection to each location. Additionally, a power source compatible with the power tool and/or an unobtrusive power cord may not be available at the job site.
Rechargeable systems for cordless tools are a common alternative to corded tools. Such systems typically include a removable rechargeable battery and a charging station. When depleted, a rechargeable battery can be removed from the tool and inserted into the charging station for charging. U.S. Pat. No. 5,144,217 describes a cordless tool battery housing and charging system that accommodates a variety of sizes and power charges of different batteries via a controlled wired charging process. Where a definition or use of a term in a reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. Such technologies as in U.S. Pat. No. 5,144,217 typically require not only removal of the battery from the tool in order to initiate charging, but also require a wired contact connection between the battery and charging station, which may be susceptible to damage due to, for example, moisture, dirt, or physical damage that prevents the battery from optimally coupling with the charging station.
Technology has been developed in an effort to alleviate these concerns via inductive or wireless charging. U.S. Pat. No. 8,482,160 describes a system whereby a plurality of wireless charging modules are placed underneath a workspace in order to inductively charge a secondary tool placed on the workspace in a region of one of the modules. However, such a system is expensive and complex to install, only enables wireless charging at the fixed regions of the modules, does not ensure that a tool is optimally located within a charging region for optimal charging, and is inapplicable to mobile applications. Further, such a system does not provide protection against a tool being unintentionally jostled and relocated during charging. For instance, a user might place a tool near a charging module with the expectation that the tool will charge. The user might then continue work with another device or tool, and in so doing, unintentionally move the tool away from the module, such that when the user again wishes to use the tool, it has not been charged as desired.
Other types of wireless charging devices have also been developed for charging tools and other devices, and typically resemble a pad on which a device is rested to initiate charging. However, such chargers present undesirable use cases when used as a tool resting surface since they are not secured to a supporting surface, nor do they secure the tool itself from unintended motion or vibration.
In one such undesirable use case, a user is operating a power drill powered by a rechargeable battery. When the battery becomes depleted, the drill becomes inoperable. In order to resume work, the user can, for example, replace the depleted battery with a charged replacement battery, or place the battery and/or tool onto a charging station and wait for the battery to recharge. Replacing the battery requires the user to obtain, store, and maintain charging for multiple batteries, which increases the expense and complexity of operating the drill, and waiting for the battery to recharge can necessitate delays in workflow before the user can resume drilling.
Additionally, conventional wireless charging stations do not guide an optimal location of the battery/tool for optimized charging, and do not secure the battery/tool in place. As a result, the battery/tool that is not optimally placed on a wireless charging station may charge slower or may fail to completely charge. Even if optimally placed, the battery/tool may become dislodged or moved due to inadvertent contact from the user, another tool or object, or other external forces such as vibrations from machinery. In another example, a charging station is positioned in a vehicle, and a battery/tool is placed thereon for charging. During transport, motion from the vehicle can jostle the battery/tool out of position and hinder or prevent charging. These types of impacts, jostling, and vibrations can also result in damage to the battery/tool when the battery/tool is unsecured.
Furthermore, the difficulties in providing external power to power tools described above also apply to providing external power to a charging station. In other words, while the tool itself may be able to operate for a short period without a wired connection, the charging station for the tool still needs to be provided with power to charge the tool. This means that the charging station presents the same risks and concerns due to obtrusive power cords as corded tools, in addition to the other deficiencies discussed above. One result has been that users obtain multiple rechargeable batteries, so that a depleted battery can be replaced even if the charging station is not available to provide power. However, maintaining multiple batteries is expensive, and may lead to cases where a user believes a battery is charged when it is not.
Therefore, what is needed is a way of maintaining a charge of a battery for a power tool such that the power tool is always in a ready-to-use condition. Additionally, what is needed is a way of charging a battery of a tool in mobile applications without interrupting its use or obstructing a workspace with cords or a charging station in such a way that optimally positions the tool for charging and protects against external motion and unintentional interruption of charging of the tool.